The present disclosure finds its genesis in a theatrical illusion which is widely known as “Pepper's ghost”. In this illusion, a viewer is made to believe that he is seeing an article which does not, in fact, exist in the setting or circumstances being viewed. The techniques involved in presenting Pepper's ghost are described hereafter. However, for now, a brief description and history of Peppers ghost is provided.
In order for the classical Peppers ghost illusion to work properly, the viewer must see clearly into a main setting, but not see into a hidden room. Unknown to the viewer, the viewer is also viewing the main setting through an angled piece of glass which, because of its placement, may be both translucent and reflective. By changing the lighting in the hidden room, the viewer may view a reflection of the lit contents of the hidden room, on the glass panel. Thus, the illusion is controlled by its illumination, and will appear and disappear when the lighting of the object, person, or the like, is turned on or off, respectively. As a result, an object or person which is reflected in the “mirror” section of the glass (e.g. the reflective surface of the glass) may seem to appear or disappear, or change into another object. While this illusion is over 100 years old, the same effect has been employed since at least the 1960's in certain modern theme parks, where objects such as reflected animated props may create the appearance of translucent “ghosts” which appear to be moving through a particular setting and interacting with props in that physical particular setting. Moreover, the images appear to be three dimensional and demonstrate a parallax effect with respect to other items on the stage.
Typically, in recent applications, a polymeric film, drawn tight within a metal frame, is used to replace the glass panel, and a projection device is used to create the image to be displayed on the polymeric film. As an example, U.S. Pat. No. 8,172,400 (O'Connell et al.) describes a projection apparatus which requires a first projection device that is arranged to generate a virtual three dimensional object by projection of the image onto to a reflected/translucent polymer film. A second projection device projects a background image; and a light source projects light onto the virtual three dimensional image. A stage arrangement may also be provided, which is placed behind the screen, upon which a presenter or actor, or a prop, or both, may be located, in order that the presenter or prop, interact with the virtual image.
In more recent applications, such as those described in US Patent publication No. US 2013/0300728 (Reichow et al.), the polymeric film or glass panel showing the reflection is replaced by a transparent front display device, such as an transparent LCD display device. In this approach, the reflective surface with its projected image, is no longer required since the virtual image may be displayed directly on the transparent front display. A background display device is positioned visually behind the transparent front display, and a background image is shown or projected directly on the background display device. The images shown on the background display device may be coordinated with the images on the transparent front display in order to create an apparent parallax effect which provides images which are similar to images from the Pepper's Ghost technique.
However, unless a visual “ghost” effect is desired, it has typically been necessary to employ a black background surface behind the virtual image so as to avoid any background image showing through the virtual image. This is because if the viewer were to see the background image through the front image, it would destroy the “holographic” effect of the virtual image.
In scenarios where a front projector with two screens (a rear-projecting screen and a background blank screen) are used, use of a front projector to generate an image on the rear-projecting screen (front screen) is problematic to the audience's viewing experience because of spill, that is, light is projected beyond the screen surface to other surfaces in the viewing environment. Spill creates a distraction to the audience away from the front screen and contributes to ambient light levels in the room. The increased light and the distraction of spill negatively impacts the audience's suspension of disbelief as they see part or all of the projected image on other surfaces as well as the actual screen, thereby negating the impact, believability of the interactive, hologramic experience.
As such, it would be beneficial to provide a newly designed and manufactured rear-projecting screen setup described herein, wherein the screen apparatus is capable of dealing with the issue of spill. The present inventors have unexpectedly discovered that the at least some of these benefits may be provided by utilizing a novel arraignment, comprising a novel rear-projecting screen, which may be utilized to view holograms by a plurality of viewers, in normal ambient lighting conditions.